A. Selection of processable fruit
Nagy et al, Citrus Science and Technology, Vol. 2, (1977), pp. 183-189, contains a general description of how citrus fruit is prepared for processing. Nagy et al teaches that during sorting, badly damaged, softened, over-ripe or otherwise low quality or unwholesome fruit is removed by hand during sorting of fruit. This reference also states that "fruit may be stored in bins for 12 to 72 hours before processing." When referring to mechanically harvested fruit, Nagy et al say the fruit should be handled as quickly as possible to minimize the time between harvesting and juicing.
Ranganna et al, "Citrus Fruits. Part II. Chemistry, Technology and Quality Review., B. Technology," CRC Critical Reviews in Food Science and Nutrition, Vol. 19 (1983), pp. 4-5, also gives a general description of the handling and sorting of citrus fruit before processing. Ranganna et al state that unwholesome fruit must be removed before processing. This reference also states that, after washing, the fruit is inspected again to remove damaged fruit missed earlier or subsequently damaged.
B. Extraction and finishing of juice
Nagy et al, supra, at pp. 188-99, gives a general description of juice extraction and finishing as it applies to the citrus industry. Nagy et al teach that the juice finisher and extractor are important to the nature, quality and characteristics of the citrus juice or concentrate, and can be adjusted to control the amount of pulp, oil, etc., in the juice. This reference specifically refers to the Brown model 400 and 700 juice extractors as producing a high quality juice that is very low in peel oil content.
Ranganna et al, supra, at pp. 6-7, also provide a general description of juice extraction and finishing. Ranganna et al teaches that the setting and operation of the juice extractor and finisher determines the yield of the juice and its quality characteristics. They state that the goal is to remove as much juice as possible from the fruit without grinding the pulp or membrane or extracting oil and juice from the peel. This reference also indicates that he pressure exerted during extraction of the juice has a significant effect on its quality and that excessive pressures produce juice having higher contents of bitter limonin, total pectin, serum viscosity, oxygenation of terpenes and aldehydes from the flavedo, septa, and seeds, etc. Conversely, juice extracted with less pressure has higher color values and better flavor.
U.S. Pat. No. 4,518,621 to Alexander, issued May 21, 1985, discloses a juice finisher for removing solids from extracted juice. In this finishing machine, extracted juice is introduced into a rotating cylindrical screen. The centrifugal force generated urges the fluid portion of the juice outwardly through the screen while retaining the solids. A plurality of paddles are arranged for rotation within the screen to uniformly spread the juice along the inside surface thereof to facilitate separation. This finisher is alleged to separate the fluid portion of the juice from the solids in "a relatively gentle manner" and "without harsh mechanical pressure being applied against" the juice entering the finisher. The main benefit alleged is the prevention of solid components from being forced through the screen.
U.S. Pat. No. 3,385,711 to Sperti, issued May 28, 1968, discloses the production of orange juice and orange juice concentrates which remain palatable throughout reasonable periods of storage under proper storage conditions. This patent states that the development of bitterness in juice products is due to pulp present in the juice. This bitterness problem is prevented by separating the pulp from the extracted juice by centrifuging, filtering or decanting and then adding pulp which does not develop undesired bitterness characteristics.